• Title/Summary/Keyword: 초음파공명분광

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공명초음파분광법을 활용한 광컨넥터용 결합소자의 결함 평가

  • 김성훈;이길성;양인영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.05a
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    • pp.48-48
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    • 2004
  • RUS(공명초음파분광법)는 비파괴 검사법의 하나로서 공명 주파수와 주파수 응답을 매우 정확하게 측정할 수 있으며, 탄성학적인 성질과 이방성을 결정하는데 이용 가능하다. Paul Heyliger와 Hassel Ledbetter는 steel block의 표면 크랙과 복합적층물의 내부 손상을 검출하는데 RUS를 사용하였으며, Jay G. Saxton은 RUS를 이용하여 chops, cracks, voids등을 검출하므로써 RUS의 비파괴 검사기능으로서의 가능성을 찾았다. 현재 광섬유 응용 제품에 많이 이용되고 있는 광커넥터는 초정밀 가공을 필요로 하는 중요한 부품으로서 optical fiber, ball lense로 구성되어진다.(중략)

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Nondestructive Examination of Optical Lens by Resonant Ultrasound Spectroscopy (공명초음파 분광법에 의한 광학기기용 렌즈의 비파괴 검사)

  • 김성훈;박상국;김영남;양인영
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.257-262
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    • 2004
  • As optical connectors dominate the performance of optical transmitters or receivers, they need an ultra-precise processing and are composed of optical fibers, ferrule and optical glass lenses. Therefore, this study suggests a nondestructive evaluation technique or a system using resonant ultrasound spectroscopy to evaluate flaws in a optical glass lens. It also conducted a nondestructive evaluation for flaws that are commonly found in a optical glass lens and reviewed the results.

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Detection of Micro-Crack Using a Nonlinear Ultrasonic Resonance Parameters (비선형 초음파공명 특성을 이용한 미세균열 탐지)

  • Cheong, Yong-Moo;Lee, Deok-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.32 no.4
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    • pp.369-375
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    • 2012
  • In order to overcome the detection limit by the current nondestructive evaluation technology, a nonlinear resonant ultrasound spectroscopy(NRUS) technique was applied for detection of micro-scale cracks in a material. A down-shift of the resonance frequency and a variation of normalized amplitude of the resonance pattern were suggested as the nonlinear parameter for detection of micro-scale cracks in a materials. A natural-like crack were produced in a standard compact tension(CT) specimen by a low cycle fatigue test and the resonance patterns were acquired in each fatigue step. As the exciting voltage increases, a down-shift of resonance frequency were increases as well as the normalized amplitude decrease. This nonlinear effects were significant and even greater in the cracked specimen, but not observed in a intact specimen.

Measurement of High Temperature Anisotropic Elastic Constants of Zr-2.5Nb Pressure Tube Materials by Resonant Ultrasound Spectroscopy (초음파공명분광법에 의한 Zr-2.5Nb 압력관 재료의 고온 이방성 탄성계수 측정)

  • Cheong, Yong-Moo;Kim, Sung-Soo;Kim, Young-Suk
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.2
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    • pp.140-148
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    • 2002
  • Anisotropic elastic constants of Zr-2.5Nb pressure tube materials were determined by a high temperature resonant ultrasound spectroscopy (RUS). The resonant frequencies were measured using alumina wave-guides and wide band ultrasonic transducers in a small furnace. The rectangular parallelepiped specimens were fabricated along with the axial, radial and circumferential direction of the pressure tube. A nine elastic stiffness tensor for orthotropic symmetry was determined in the range of room temperature ${\sim}500^{\circ}C$. As the temperature increases, the elastic constant tensor, cij gradually decreases. Higher elastic constants along the transverse direction compared to those along the axial or radial direction are similar to the case of Young's modulus or shear modulus. A crossing of shear elastic constants along axial direction and radial direction was observed near $150^{\circ}C$. This fact corresponds to the crossing of c44 and c66 of single crystal zirconium.

Development of Laser-Based Resonant Ultrasound Spectroscopy(Laser-RUS) System for the Detection of Micro Crack in Materials (재료의 미세결함 검출을 위한 레이저 공명 초음파 분광(Laser-RUS)시스템 개발)

  • Kang, Young-June;Kim, Jin-Soo;Park, Seung-Kyu;Baik, Sung-Hoon;Choi, Nag-Jung
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.1
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    • pp.41-48
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    • 2010
  • Non-contacting, laser-based resonant ultrasound spectroscopy (L-RUS) was applied to characterize the microstructure of a material. L-RUS is widely used by virtue of its many features. Firstly, L-RUS can be used to measure mechanical damping which related to the microstructural variations (grain boundary, grain size, precipitation, defects, dislocations etc). Secondly, L-RUS technology can be applied to various areas, such as the noncontact and nondestructive quality test for precision components as well as noncontact and nondestructive materials characterization. In addition, L-RUS technology can measure the whole field resonant frequency at once. In this paper, we evaluated material characteristics such as resonant frequency, nonlinear propagation characteristic through the development of Laser-Based Resonant Ultrasound spectroscopy (Laser-RUS) System for the detection of Micro Crack in Materials.

MR Spectroscopy and Diffusion Weighted Imaging Findings of Primary Non-Hodgkin Lymphoma of the Breast: Two Case Reports (유방에 발생한 일차성 비호지킨림프종의 자기공명 분광법 및 확산강조 영상: 2예)

  • Nam, Sang Yu;Yoo, Eun Young;Choi, Hye-Young
    • Investigative Magnetic Resonance Imaging
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    • v.18 no.2
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    • pp.176-181
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    • 2014
  • Primary non-Hodgkin lymphoma (NHL) of the breast is a very rare disease, and the mammographic and ultrasonographic findings of breast lymphoma are variable. There are several reports of magnetic resonance (MR) imaging findings in patients with breast lymphomas; however, few reports have described the findings observed on MR spectroscopy or the features of diffusion weighted (DW) imaging. The authors report the findings of classical MR imaging, MR spectroscopy and DW imaging of a 48-year-old woman and a 40-year-old woman with primary non-Hodgkin's lymphoma of breasts. Mammography and breast ultrasonography revealed a mass with circumscribed margin. The mass showed strong enhancement after contrast injection on MR imaging. DW imaging showed reduced diffusion and high-amplitude choline (Cho) peak at 3.22 ppm was detected by single voxel MR spectroscopy which was consistent with malignancy.

Measurement of Dynamic Elastic Constants of RPV Steel Weld due to Localized Microstructural Variation (원자로 용접부의 국부적 미세조직 변화에 따른 동적탄성계수 측정)

  • Cheong, Yong-Moo;Kim, Joo-Hag;Hong, Jun-Hwa;Jung, Hyun-Kyu
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.5
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    • pp.390-396
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    • 2000
  • The dynamic elastic constants of the simulated weld HAZ (heat-affected zone) of SA 508 Class 3 reactor pressure vessel (RPV) steel were investigated by resonant ultrasound spectroscopy (RUS). The resonance frequencies of rectangular parallelepiped samples woe calculated from the initial estimates of elastic stiffness $c_{11},\;c_{12}\;and\;c_{44}$ with an assumption of isotropic property, dimension and density. Through the comparison of calculated resonant frequencies with the measured resonant frequencies by RUS, very accurate elastic constants of SA 508 Class 3 steel were determined by iteration and convergence processes. Clear differences of Youngs modulus and shear modulus were shown from samples with different thermal cycles and microstructures. Youngs modulus and shear modulus of samples with fine-grained bainite were higher than those with coarse-grained tempered martensite. This tendency was confirmed from other results such as micro-hardness test.

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The Nondestructive Inspection of the Ferrule for the Optical Connector by Resonant Ultransound Spectroscopy (공명초음파분광법에 의한 광컨넥터용 Ferrule의 비파괴검사)

  • 백경윤;황재중;양순호;민한기;양인영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1345-1348
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    • 2003
  • The Ferrule for the Optical Communication Connector is the product to set the optical ares of an optical fiber very precisely. Therefore, it is required high expectations such as high dimensional precision and new including flaws. Up to new the optical instrument has been used for the defeat and shape inspection of the ferrule, but in the paper we examined the detectable defeat and expectation by using Resonant Ultrasound Spectroscopy(RUS). The RUS is the measurement which is to excite specimen and to inspect the difference at natural frequency pattern between acceptable specimen and specimen which has some defeats. We analyzed the difference of natural frequency pattern in the experiment using Spectrum Analyzer. And we compared the results in the experiment with those in the simulation from the explicit finite elements code, Nastran.

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Nondestructive Evaluation of the Flaw in a Ceramic Ferrule by Resonant Ultrasound Spectroscopy (공명초음파분광법을 이용한 페롤의 비파괴결함평가)

  • 김성훈;백경윤;김영남;양인영
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.5
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    • pp.108-117
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    • 2004
  • In this paper, a measuring NDT(nondestructive testing) system using RUS(Resonant Ultrasound Spectroscopy) was built for nondestructive evaluation of the flaw in a ceramic Ferrule. The principle of RUS is that the mechanical resonant frequency of the materials depends on density, and the coefficient of elasticity. The RUS system is the measuring which is to exite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and specimen which has some defects. RUS system is configured of spectrum analyzer, power amplifier, PZT sensor and support frame. For defect evaluation by the RUS, we performed to measure natural frequency of Ferrule, both acceptable and cracked. In the case of Ferrule, the resonant frequency of cracked-Ferrule existed to higher frequency band than acceptable-Ferrule.